#include "des.h"
#include <assert.h>
#include "misc.h"

static int IP_Table[64] = {  57,49,41,33,25,17,9,1,
			 59,51,43,35,27,19,11,3,
			 61,53,45,37,29,21,13,5,
			 63,55,47,39,31,23,15,7,
			 56,48,40,32,24,16,8,0,
			 58,50,42,34,26,18,10,2,
			 60,52,44,36,28,20,12,4,
			 62,54,46,38,30,22,14,6}; 

static int IP_1_Table[64] = {39,7,47,15,55,23,63,31,
		   38,6,46,14,54,22,62,30,
		   37,5,45,13,53,21,61,29,
		   36,4,44,12,52,20,60,28,
		   35,3,43,11,51,19,59,27,
		   34,2,42,10,50,18,58,26,
		   33,1,41,9,49,17,57,25,
		   32,0,40,8,48,16,56,24};


static int E_Table[48] = {31, 0, 1, 2, 3, 4,
	              3,  4, 5, 6, 7, 8,
	              7,  8,9,10,11,12,
	              11,12,13,14,15,16,
	              15,16,17,18,19,20,
	              19,20,21,22,23,24,
	              23,24,25,26,27,28,
	              27,28,29,30,31, 0};


static int P_Table[32] = {15,6,19,20,28,11,27,16,
				  0,14,22,25,4,17,30,9,
				  1,7,23,13,31,26,2,8,
				  18,12,29,5,21,10,3,24};


static int S[8][4][16] =
	        {{{14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7},
	        {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8},
	        {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0},
	        {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13}},
	        
	        {{15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10},
	        {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5},
	        {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15},
	        {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}},
	        
	        {{10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8},
	        {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1},
	          {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},
	        {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}},
	        
	        {{7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15},
	        {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9},
	        {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4},
	        {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14}},
	        
	        {{2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9},
	        {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6},
	        {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14},
	        {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}},
	        
	        {{12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11},
	        {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8},
	        {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6},
	        {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13}},
	        
	        {{4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1},
	        {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6},
	        {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2},
	        {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12}},
	        
	        {{13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7},
	        {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2},
	        {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8},
	        {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}}};

static int PC_1[56] = {56,48,40,32,24,16,8,
	          0,57,49,41,33,25,17,
	          9,1,58,50,42,34,26,
	          18,10,2,59,51,43,35,
	          62,54,46,38,30,22,14,
	          6,61,53,45,37,29,21,
	          13,5,60,52,44,36,28,
	          20,12,4,27,19,11,3};


static int PC_2[48] = {13,16,10,23,0,4,2,27,
	          14,5,20,9,22,18,11,3,
	          25,7,15,6,26,19,12,1,
	          40,51,30,36,46,54,29,39,
	          50,44,32,46,43,48,38,55,
	          33,52,45,41,49,35,28,31};


static int MOVE_TIMES[16] = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};


int ByteToBit(ElemType ch, ElemType bit[8]){
	int cnt;
	for(cnt = 0;cnt < 8; cnt++){
		*(bit+cnt) = (ch>>cnt)&1;
	}
	return 0;
}


int BitToByte(ElemType bit[8],ElemType *ch){
	int cnt;
	for(cnt = 0;cnt < 8; cnt++){
		*ch |= *(bit + cnt)<<cnt;
	}
	return 0;
}


int Char8ToBit64(ElemType ch[8],ElemType bit[64]){
	int cnt;
	for(cnt = 0; cnt < 8; cnt++){		
		ByteToBit(*(ch+cnt),bit+(cnt<<3));
	}
	return 0;
}


int Bit64ToChar8(ElemType bit[64],ElemType ch[8]){
	int cnt;
	memset(ch,0,8);
	for(cnt = 0; cnt < 8; cnt++){
		BitToByte(bit+(cnt<<3),ch+cnt);
	}
	return 0;
}


int DES_MakeSubKeys(ElemType key[64],ElemType subKeys[16][48]){
	ElemType temp[56];
	int cnt;
	DES_PC1_Transform(key,temp);
	for(cnt = 0; cnt < 16; cnt++){
		DES_ROL(temp,MOVE_TIMES[cnt]);
		DES_PC2_Transform(temp,subKeys[cnt]);
	}
	return 0;
}


int DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]){
	int cnt;	
	for(cnt = 0; cnt < 56; cnt++){
		tempbts[cnt] = key[PC_1[cnt]];
	}
	return 0;
}


int DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]){
	int cnt;
	for(cnt = 0; cnt < 48; cnt++){
		tempbts[cnt] = key[PC_2[cnt]];
	}
	return 0;
}


int DES_ROL(ElemType data[56], int time){	
	ElemType temp[56];

	
	memcpy(temp,data,time);
	memcpy(temp+time,data+28,time);
	
	
	memcpy(data,data+time,28-time);
	memcpy(data+28-time,temp,time);

	
	memcpy(data+28,data+28+time,28-time);
	memcpy(data+56-time,temp+time,time);	

	return 0;
}


int DES_IP_Transform(ElemType data[64]){
	int cnt;
	ElemType temp[64];
	for(cnt = 0; cnt < 64; cnt++){
		temp[cnt] = data[IP_Table[cnt]];
	}
	memcpy(data,temp,64);
	return 0;
}


int DES_IP_1_Transform(ElemType data[64]){
	int cnt;
	ElemType temp[64];
	for(cnt = 0; cnt < 64; cnt++){
		temp[cnt] = data[IP_1_Table[cnt]];
	}
	memcpy(data,temp,64);
	return 0;
}


int DES_E_Transform(ElemType data[48]){
	int cnt;
	ElemType temp[48];
	for(cnt = 0; cnt < 48; cnt++){
		temp[cnt] = data[E_Table[cnt]];
	}	
	memcpy(data,temp,48);
	return 0;
}


int DES_P_Transform(ElemType data[32]){
	int cnt;
	ElemType temp[32];
	for(cnt = 0; cnt < 32; cnt++){
		temp[cnt] = data[P_Table[cnt]];
	}	
	memcpy(data,temp,32);
	return 0;
}


int DES_XOR(ElemType R[48], ElemType L[48] ,int count){
	int cnt;
	for(cnt = 0; cnt < count; cnt++){
		R[cnt] ^= L[cnt];
	}
	return 0;
}


int DES_SBOX(ElemType data[48]){
	int cnt;
	int line,row,output;
	int cur1,cur2;
	for(cnt = 0; cnt < 8; cnt++){
		cur1 = cnt*6;
		cur2 = cnt<<2;
		
		
		line = (data[cur1]<<1) + data[cur1+5];
		row = (data[cur1+1]<<3) + (data[cur1+2]<<2)
			+ (data[cur1+3]<<1) + data[cur1+4];
		output = S[cnt][line][row];

		
		data[cur2] = (output&0X08)>>3;
		data[cur2+1] = (output&0X04)>>2;
		data[cur2+2] = (output&0X02)>>1;
		data[cur2+3] = output&0x01;
	}	
	return 0;
}


int DES_Swap(ElemType left[32], ElemType right[32]){
	ElemType temp[32];
	memcpy(temp,left,32);	
	memcpy(left,right,32);	
	memcpy(right,temp,32);
	return 0;
}


int DES_EncryptBlock(ElemType plainBlock[8], ElemType subKeys[16][48], ElemType cipherBlock[8]){
	ElemType plainBits[64];
	ElemType copyRight[48];
	int cnt;

	Char8ToBit64(plainBlock,plainBits);		
	
	DES_IP_Transform(plainBits);

	
	for(cnt = 0; cnt < 16; cnt++){		
		memcpy(copyRight,plainBits+32,32);
		
		DES_E_Transform(copyRight);
		
		DES_XOR(copyRight,subKeys[cnt],48);	
		
		DES_SBOX(copyRight);
		
		DES_P_Transform(copyRight);
		
		DES_XOR(plainBits,copyRight,32);
		if(cnt != 15){
			
			DES_Swap(plainBits,plainBits+32);
		}
	}
	
	DES_IP_1_Transform(plainBits);
	Bit64ToChar8(plainBits,cipherBlock);
	return 0;
}


int DES_DecryptBlock(ElemType cipherBlock[8], ElemType subKeys[16][48],ElemType plainBlock[8]){
	ElemType cipherBits[64];
	ElemType copyRight[48];
	int cnt;

	Char8ToBit64(cipherBlock,cipherBits);		
	
	DES_IP_Transform(cipherBits);
	
	
	for(cnt = 15; cnt >= 0; cnt--){		
		memcpy(copyRight,cipherBits+32,32);
		
		DES_E_Transform(copyRight);
		
		DES_XOR(copyRight,subKeys[cnt],48);		
		
		DES_SBOX(copyRight);
		
		DES_P_Transform(copyRight);		
		
		DES_XOR(cipherBits,copyRight,32);
		if(cnt != 0){
			
			DES_Swap(cipherBits,cipherBits+32);
		}
	}
	
	DES_IP_1_Transform(cipherBits);
	Bit64ToChar8(cipherBits,plainBlock);
	return 0;
}


int DES_Encrypt(const char *plainStr, const char *keyStr,char *cipherStr){
	ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
	ElemType bKey[64];
	ElemType subKeys[16][48];
	int plainLen = strlen(plainStr) + 1; //including the \0
	int encryptLen = 0;
	
	memset(keyBlock, 0, sizeof(keyBlock));
	strncpy(keyBlock, keyStr, 8);
	keyBlock[7] = 65;
	
	Char8ToBit64(keyBlock,bKey);
	
	DES_MakeSubKeys(bKey,subKeys);

	
	while(plainLen - encryptLen >= 8){
		memcpy(plainBlock, plainStr + encryptLen, 8);
		DES_EncryptBlock(plainBlock,subKeys,cipherBlock);
		memcpy(cipherStr + encryptLen, cipherBlock,8);	
		encryptLen += 8;
	}
	if(encryptLen < plainLen){
		memset(plainBlock, 0, 8);
		memcpy(plainBlock, plainStr + encryptLen, plainLen - encryptLen);
		DES_EncryptBlock(plainBlock,subKeys,cipherBlock);
		memcpy(cipherStr + encryptLen, cipherBlock,8);
		encryptLen += 8;
	}
	return encryptLen;
}


int DES_Decrypt(const char *cipherStr, const int len, const char *keyStr,char *plainStr)
{
	ElemType plainBlock[8],cipherBlock[8],keyBlock[8];
	ElemType bKey[64];
	ElemType subKeys[16][48];
	int decryptLen = 0;
	
	memset(keyBlock, 0, sizeof(keyBlock));
	strncpy(keyBlock, keyStr, 8);
	keyBlock[7] = 65;

	Char8ToBit64(keyBlock,bKey);
	DES_MakeSubKeys(bKey,subKeys);
			
	while(decryptLen < len){
		
		memcpy(cipherBlock,cipherStr+decryptLen,8);
		DES_DecryptBlock(cipherBlock,subKeys,plainBlock);
		memcpy(plainStr + decryptLen, plainBlock, 8);
		decryptLen += 8;
	}
	
	return decryptLen;
}

char ENC(char theCh)
{
 char ch = (theCh & 0x03F) + ' ';
     
 switch (ch)
  {
   case ' '  : ch = 'm';
               break;
   case '['  : ch = 'd';
               break;
   case '\\' : ch = 'e';
               break;
   case ']'  : ch = 'f';
               break;
   case '^'  : ch = 'g';
               break;
   case '\'' : ch = 'h';
               break;
  }
 return(ch);
}

char* uencode ( const char *in, char* out )
{
    int c1, c2, c3, c4;
     
    c1 = (*in >> 2) & 0x3F;
    c2 = (*in << 4) & 0x30 | (in[1] >> 4) & 0x0F; 
    c3 = (in[1] << 2) & 0x3C | (in[2] >> 6) & 0x03; 
    c4 = in[2] & 0x3F;
    *out = ENC(c1); out++;
    *out = ENC(c2); out++;
    *out = ENC(c3); out++;
    *out = ENC(c4); out++;
	return out;
}

int DES_Encrypt2Char(const char *plainStr, const char *keyStr,char *cipherStr/*[128]*/)
{
	if (strlen(plainStr) > 80 || strlen(plainStr) == 0){
		return 0;
	}

	char tmpOut[128];
	memset(tmpOut, 0, sizeof(tmpOut));
	int tmplen = DES_Encrypt(plainStr, keyStr, tmpOut);
	assert(tmplen < 90);

	char *tmpIndex = tmpOut;
	char* out = cipherStr;
	for (; tmpIndex - tmpOut < tmplen; tmpIndex+=3){
		out = uencode(tmpIndex, out);
	}
	assert((out - cipherStr)%4==0);
	return (out - cipherStr);
}

char DECN ( char ch )
{
 switch (ch)
  {
   case 'm' : ch = ' ';
	      break;
   case 'd' : ch = '[';
	      break;
   case 'e' : ch = '\\';
	      break;
   case 'f' : ch = ']';
	      break;
   case 'g' : ch = '^';
	      break;
   case 'h' : ch = '\'';
	      break;
  }
    
 ch = (ch - ' ') & 0x03F;
     
 return(ch);
}

char* udecode ( const char *in, char* out)
{
     
	*out = DECN(*in) << 2 | DECN(in[1]) >> 4; 
	out ++;
	*out = DECN(in[1]) << 4 | DECN(in[2]) >> 2; 
	out ++;	
	*out = DECN(in[2]) << 6 | DECN(in[3]);
	out ++;
  return out;
}

int DES_DecryptFromChar(const char *cipherStr, const int len, const char *keyStr,char *plainStr/*[128]*/)
{
	assert(len%4 == 0);
	const char* inIndex = cipherStr;
	char tmpOut[128];
	memset(tmpOut, 0, sizeof(tmpOut));
	char* outIndex = tmpOut;
	for (; inIndex < cipherStr + len; inIndex+=4){
		outIndex = udecode(inIndex, outIndex);
	}
	return DES_Decrypt(tmpOut, (outIndex-tmpOut)/8*8, keyStr, plainStr);

}

